Auditory Canal
Also called the ear canal. A short tube about 1 inch (2.5 cm) long that directs sound to the eardrum.

Auditory Nerve
Also called the vestibulocochlear nerve or acoustic nerve. Acts like a telephone line to the brain. The electrical signals generated by the hair cells are sent to the brain by this nerve.

Auricle
The visible part of the outer ear - also called the pinna. If you can wiggle your ears, the auricle is what you wiggle.

Control
A way for a musician to modify the musical instrument to affect the sound it produces. Musical instruments, including the voice, allow musicians to change pitch, loudness and even the tone color to some degree. For example, a trumpet can play the same note loud, brassy, and bright, or softer with a mellow tone

Frequency
The number of times a vibrating object oscillates (moves back and forth) in one second. Fast movements produce high frequency sound (high pitch/tone), but slow movements mean the frequency (pitch/tone) is low.

Inner Ear
A complex structure of interconnected fluid-filled chambers and canals within the bone of the skull - One portion of the inner ear is not involved in hearing, but instead provides a sense of balance. The other portion of the inner ear, called the cochlea, is the organ of hearing.

Larynx
Often called the ‘voice box,’ it is located at the top of the windpipe at the lower end of the throat. It is made up of muscles, membranes and cartilages, and contains the vocal folds (vocal cords).

Oscillation
Back and forth movement that repeats regularly between two fixed positions.

Ossicles
Three bones found in the ears of all mammals (the malleus, the incusand the stapes or hammer, anvil and stirrup). These bones are the smallest bones in a person’s body and they act like a system of levers.

Outer Ear
The external part of the ear which includes the pinna (the part you can wiggle) and the ear canal.

Pinna
The visible part of the outer ear, also called the auricle - if you can wiggle your ears, the pinna is what you wiggle

Pitch
How high or low a tone sounds to a person. High frequencysound has a high pitch or tone (treble notes), but low frequency has a low/deep pitch or tone (bass notes). High sounds are usually above 2000 Hertz and low below 200 Hertz.

Sensitivity
How strongly an organ or living thing reacts to something. For example, the ears are sensitive to sound while the eyes are sensitive to light.

Sonar
Sound Navigation And Ranging, is the process of listening to specific sounds to determine where objects are located. In active SONAR, a sound is transmitted and the listener uses its echo to locate objects. In passive SONAR, the listener uses the sounds emitted directly from the source of the sounds.

Sound Pollution
The concentration of sound to levels harmful to the natural environment (including humans).

Sound Source
Whatever object makes the sound. All of these are sources of sound: two hands clapping together, a person speaking or singing, a submarine echolocating, a radio playing, birds chirping, ocean waves crashing on the beach.

Sound WaveVibrations of air molecules that travel through air carrying energy with them. Sound waves can also travel through water and solids, but cannot travel in space where there are no molecules to vibrate. When sound travels through air, the molecules do not actually move to a new location, instead each set of molecules "bumps" the molecules next to it, progressively transferring motion to new sets of molecules farther and farther away from the sound source until the wave motion dies out. Play with the "Sound" tab on this simulation to see sound travel through air.

Spectrum Analyzer
A device used to see the different waves (frequencies) that make up a sound.

Speed of Sound
The speed at which sound travels. This is very important for scientists who study sound. In air sound travels 343 meters in 1 second (767 miles per hour), but in water sound travels 1500 meters in 1 second (3350 miles per hour). Compare these speeds to cars traveling on the highway at 65 miles per hour.

Vestibulocochlear Nerve
Also called the auditory nerve or acoustic nerve. Acts like a telephone line to the brain. The electrical signals generated by the hair cells are sent to the brain by this nerve.

Vocal Folds
Often called the 'vocal cords', are made up of two membranes on the sides of our larynx (voice box). We talk by squeezing them close together as the lungs push air between them causing them to vibrate.